Recently, a rechargeable battery that can be repeatedly charged and discharged has been variously used as an energy source of a wireless mobile device. In addition, the rechargeable battery has attracted attention as an energy source of an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like, which have been proposed as a solution to solve air pollution from conventional gasoline vehicles and diesel vehicles using fossil fuels.
In small-sized mobile devices, one or more battery cells are used per device, while in middle- or large-sized devices such as vehicles, a middle- or large-sized battery pack in which a large number of battery cells are electrically connected is used due to necessity of high output and large capacity.
Since it is preferable that the middle- or large-sized battery pack is manufactured with as small a size and as light a weight as possible, a prismatic battery, a pouch-type battery, and the like, which may be stacked with a high degree of integration and have light weight compared to capacity, are mainly used as a battery cell of the middle- or large-sized battery pack. Particularly, recently, a pouch-type battery using an aluminum laminate sheet or the like as an exterior member has attracted a great deal of attention due to its advantages such as light weight, low manufacturing cost, and easy shape modification.
Since the battery cells included in the middle- or large-sized battery pack are rechargeable batteries, a high-output large-capacity rechargeable battery generates a large amount of heat during a charging and discharging process. Particularly, since the laminate sheet of the pouch-type battery widely used in the battery pack is coated with a polymer material having low thermal conductivity, it is difficult to effectively reduce a temperature of all of the battery cells.
When heat generated during the charging and discharging process is not effectively eliminated, heat accumulation may occur, which may accelerate deterioration of the battery cell and possibly cause ignition or explosion. Therefore, the high-power large-capacity battery pack requires a cooling system for cooling the battery cells included in the battery pack.
Generally, the battery pack is manufactured by very densely stacking a plurality of battery cells, and adjacent battery cells are stacked to be spaced apart from each other by a predetermined interval so as to remove heat generated during charging and discharging. For example, the battery cells themselves may be sequentially stacked while being spaced apart from each other by a predetermined interval without a separate member, or when the battery cells have low mechanical rigidity, they may be accommodated in a cartridge or the like in a combination of one or more, and then a plurality of such cartridges may be stacked to form the battery pack.
Conventionally, a coolant channel is formed between the battery cells so as to effectively eliminate the heat generated between the stacked and arranged battery cells, or after forming cooling fins between the battery cells, the heat generated in the battery cells is cooled by an air-cooling or water-cooling method from the cooling member mounted on the outside of the battery pack through the cooling fins.
FIG. 1 illustrates a schematic view of a structure of a conventional battery pack 100, and FIG. 2 illustrates a top plan view of a battery pack of FIG. 1 of a cooling type. In the conventionally battery pack 100, cooling fins 20a, 20b, 20c, and 20d are interposed between stacked battery cells 10a, 10b, 10c, 10d, and 10e. 
However, when the cooling fins 20a, 20b, 20c, and 20d are interposed between the battery cells 10a, 10b, 10c, 10d, and 10e, the number of components is increased, and a process such as welding or fastening between the cooling fins and the cooling member is added, whereby weight of the battery pack may be increased. In addition, since the cooling fins and the cooling members are thermally coupled to each other with a heat radiation pad therebetween and the cooling member is formed with a coolant channel, manufacturing cost is increased and a manufacturing process is complicated.
Since the cooling fins 20a, 20b, 20c, and 20d are interposed between the battery cells 10a, 10b, 10c, 10d, and 10e, a thickness of the battery pack 100 increases, and heat radiation efficiency is not particularly high as compared with an area in which the cooling fin 20a and the battery cell 10a are in contact with each other.
Therefore, there is a high need for a battery pack capable of eliminating the cooling fins while providing high-power large-capacity power, obtaining a heat radiating effect equivalent to conventional cooling efficiency, and reducing the thickness and the weight of the battery pack.